chore(charts): add prometheus rule support

Author: duanhongyi

charts/victoriametrics/templates/victoriametrics/vmagent/vmagent-clusterrole.yaml

@@ -32,6 +32,14 @@ rules:
       - get
       - list
       - watch
+  - apiGroups:
+      - "discovery.k8s.io"
+    resources:
+      - endpointslices
+    verbs:
+      - get
+      - list
+      - watch
   - nonResourceURLs:
       - "/metrics"
     verbs: